13,028 research outputs found

    Fontes e freqüências de aplicação de nitrogênio via água de irrigação no mamoeiro.

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    A escassez ou má distribuição das chuvas no Nordeste e em outras regiões do Brasil, como o Centro Oeste, o Sudeste e o Sul torna obrigatório o uso da irrigação. A irrigação, por sua vez, tem trazido consigo a atividade de aplicação de adubos via água, ou a fertirrigação, que vem sendo usada em ritmo crescente de fruticultores. O nitrogênio (N) é o elemento requerido em maior quantidade, pelo mamoeiro seguido posteriormente pelo potássio (K) e pelo cálcio (Ca) conforme Cunha & Haag (1980) citado por Oliveira (2002). A dinâmica do N difere conforme a fonte, sendo que no caso das fontes amidicas e amoniacais o N ocorrerá no solo na forma de amônio inicialmente e de nitrato posteriormente; na forma nítrica, o N ocorrerá na forma de nitrato o que indica maior mobilidade do mesmo no solo com possibilidades inclusive de lixiviação.bitstream/item/50972/1/comunicado-111-1.pd

    HIV-1 mother-to-child transmission in Brazil (1994\u20132016): a time series modeling

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    HIV-1 mother-to-child transmission (HIV-1 MTCT), is an important cause of children mortality worldwide. Brazil has been traditionally praised by its HIV/Aids program, which provides free-of-charge care for people living with HIV-1. Using public epidemiology and demographic databases, we aimed at modeling HIV-1 MTCT prevalence in Brazil through the years (1994\u20132016) and elaborate a statistical model for forecasting, contributing to HIV-1 epidemiologic surveillance and healthcare decision-making. We downloaded sets of live births and mothers\u2019 data alongside HIV-1 cases notification in children one year old or less. Through time series modeling, we estimated prevalence along the years in Brazil, and observed a remarkable decrease of HIV-1 MTCT between 1994 (10 cases per 100,000 live births) and 2016 (five cases per 100,000 live births), a reduction of 50%. Using our model, we elaborated a prognosis for each Brazilian state to help HIV-1 surveillance decision making, indicating which states are in theory in risk of experiencing a rise in HIV-1 MTCT prevalence. Ten states had good (37%), nine had mild (33%), and eight had poor prognostics (30%). Stratifying the prognostics by Brazilian region, we observed that the Northeast region had more states with poor prognosis, followed by North and Midwest, Southeast and South with one state of poor prognosis each. Brazil undoubtedly advanced in the fight against HIV-1 MTCT in the past two decades. We hope our model will help indicating where HIV-1 MTCT prevalence may rise in the future and support government decision makers regarding HIV-1 surveillance and prevention

    Star-forming dwarf galaxies in the Virgo cluster: the link between molecular gas, atomic gas, and dust

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    We present 12^{12}CO(1-0) and 12^{12}CO(2-1) observations of a sample of 20 star-forming dwarfs selected from the Herschel Virgo Cluster Survey, with oxygen abundances ranging from 12 + log(O/H) ~ 8.1 to 8.8. CO emission is observed in ten galaxies and marginally detected in another one. CO fluxes correlate with the FIR 250 μ\mum emission, and the dwarfs follow the same linear relation that holds for more massive spiral galaxies extended to a wider dynamical range. We compare different methods to estimate H2 molecular masses, namely a metallicity-dependent CO-to-H2 conversion factor and one dependent on H-band luminosity. The molecular-to-stellar mass ratio remains nearly constant at stellar masses <~ 109^9 M⊙_{\odot}, contrary to the atomic hydrogen fraction, MHI_{HI}/M∗_*, which increases inversely with M∗_*. The flattening of the MH2_{H_2}/M∗_* ratio at low stellar masses does not seem to be related to the effects of the cluster environment because it occurs for both HI-deficient and HI-normal dwarfs. The molecular-to-atomic ratio is more tightly correlated with stellar surface density than metallicity, confirming that the interstellar gas pressure plays a key role in determining the balance between the two gaseous components of the interstellar medium. Virgo dwarfs follow the same linear trend between molecular gas mass and star formation rate as more massive spirals, but gas depletion timescales, τdep\tau_{dep}, are not constant and range between 100 Myr and 6 Gyr. The interaction with the Virgo cluster environment is removing the atomic gas and dust components of the dwarfs, but the molecular gas appears to be less affected at the current stage of evolution within the cluster. However, the correlation between HI deficiency and the molecular gas depletion time suggests that the lack of gas replenishment from the outer regions of the disc is lowering the star formation activity.Comment: 19 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

    Prognostic value of CA125 in advanced heart failure patients

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    INTRODUCTION: Serum levels of CA125 are often high in advanced heart failure (AHF) patients. AIM: To determine the predictive value of CA125 in forecasting the occurrence of death or cardiac transplantation in an AHF population. METHODS: 88 AHF patients referred for heart transplantation were divided into 2 groups based on CA125 levels: normal (CA125/=38 U/mL). Events (death or heart transplant) were monitored over a period of 13+/-7 months after CA125 determination. RESULTS: Patients with elevated CA125 (n=65) had significantly lower blood pressure, body mass index, serum sodium and peak exercise oxygen consumption, while B-type natriuretic peptide levels were significantly higher. The combined primary endpoint (death or heart transplant) rate was 39.4% and 62.3% in normal and elevated CA125 groups, respectively (p=0.029). Multivariate regression analysis showed that CA125 and sodium levels were the only independent predictors of the combined endpoint. CONCLUSION: In AHF patients, plasma CA125 was an effective prognostic marker. Its determination may contribute to better risk stratification in this population
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